Operation CHARM: Car repair manuals for everyone.
Manuals through 2025 now available!

Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.

LEMON is the spiritual successor to CHARM, I recommend you try it!

Link: lemon-manuals.la or lemon-manuals.org.ua

(Some people have issue connecting. LEMON is investigating. For now, use Firefox or change your DNS server)

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Servo Actuation Test


Servo Actuation Test:




Servo Unit Operation:






The servo actuation test checks the cruise control servo to see if the vent solenoids and the vacuum solenoids function and hold vacuum.

It is possible for the system to be electronically functional, yet the solenoids may not seat correctly or leak vacuum. This can result in intermittent or no function of the servo.

Performing this test will help avoid replacement of good components.